The present invention relates to a single-in-line integrated electronic component and to a process for manufacturing the same.
It is known that the usual integrated electronic components include a container or package of epoxy and/or silicone thermosetting resin, made by molding around a metallic frame previously provided with a thermic dissipator and with a semiconductor wafer or "chip".
These known electronic components, commonly called "molded", show several drawbacks as regards the cost and the performance (reliability and quality):
(a) possibility of breakage and/or damage of the semiconductor wafer, due to the fact that the molding and subsequent operation (separation of the several frame units from a single initial metallic strip or "cropping", polishing of the contacts from the resin flashes or "deflashing") are carried out in presence of the semiconductor wafer;
(b) degrading effects (of mechanical, chemical, thermal type) induced by the resin on the wafer;
(c) poor versatility, since every structural change involves valuable alterations of the molds for the shearing of the metallic frame and the molding of the resin package;
(d) reduced possibility of carrying out automatically the final testing and marking processes, which are to be carried out on the single components already separated from each other;
(e) problems for the fastening of the inner dissipator of the component to the common outer dissipator, this causing presently a partial raising of the component which complicates and makes longer the thermic heat dissipation path.
There are on the market, on the other hand, so-called "pre-molded" electronic components, in which the dissipator and the semiconductor wafer or chip, and then a resin cover or cap, are applied in a suitable space provided inside a resin package previously molded on the metallic frame.
These components are however known only in the "dual-in-line" embodiment, that is with electric contacts coming out from two opposed sides of the package.
Object of the present invention, on the contrary, is to realize an integrated electronic component of the "single-in-line" type, that is with electric contacts coming out from one side of the package.
Another object of the present invention is to realize a single-in-line electronic component, which is exempt from the above indicated drawbacks of the present "molded" components.
Still another object of the present invention is to realize a single-in-line electronic component, which offers an original and efficient solution of the problem of the fastening of the component to the outer dissipator.
According to the invention such objects are reached by a single-in-line integrated electronic component, characterized in that it comprises an insulating package pre-molded on a metallic frame provided with electric contacts, a thermic dissipator, a semiconductor chip housed in a space of said package on said thermic dissipator and electrically connected to said contacts, and an insulating cover arranged to close said space and provided with a bent lateral extension for fastening and thrusting the component towards a support surface. Otherwise stated, the electronic component according to the invention therefore represents the application of the "pre-molding" art (that is the previous molding of the resin package) to a "single-in-line" component, with the important addition of the provision of a cover which has also the function of providing the fastening and the correct thrusting of the component towards the support surface, that is towards the outer dissipator.
There result the following important advantages with respect to the presently used "molded" components:
(a) the three parts which form the package ("pre-molded" frame, dissipator and cover) may be treated separately;
(b) the dangerous operations are carried out while the semiconductor chip is absent;
(c) the resin is not in close contact with the chip;
(d) the versatility is high and the changes involve low costs;
(e) the fastening by means the same package closing cover allows the component to be kept well adherent to the support surface, this helping the direct heat dissipation through the shortest way.
Still according to the invention there is further provided a process for manufacturing the above said component, which after the usual preparation of a strip of metallic frames (one for each component) made integral with each other by metallic connecting tongues, includes the molding, on said frames, of respective insulating packages made integral with each other by insulating bridges destined by being cut only at the end of the process.
Once the dissipator, the semiconductor chip and the cover have been applied and the cutting of the metallic frame connecting tongues ("cropping") has been carried out, this obviously allows to prosecute the several testing and marking operations with the several components electrically separated but mechanically connected to each other, with consequent possibility of complete automation of the entire process and particularly of the above said final operations.